Bourbaki dangerous bend symbol: Difference between revisions
reword on Knuth |
m |
||
Line 6: | Line 6: | ||
Some passages are designed to guard the reader against serious errors, where he risks falling; these passages are signposted in the margin by the sign ☡ ("dangerous bend") |
Some passages are designed to guard the reader against serious errors, where he risks falling; these passages are signposted in the margin by the sign ☡ ("dangerous bend") |
||
|source=Nicholas Bourbaki's description of the symbol in several textbooks<ref>See, for example, ''[http://books.google.com/books?id=VDGifaOQogcC&pg=SA1-PA5 Théorie des ensembles]'', p. I-8.</ref> |
|source=— Nicholas Bourbaki's description of the symbol in several textbooks<ref>See, for example, ''[http://books.google.com/books?id=VDGifaOQogcC&pg=SA1-PA5 Théorie des ensembles]'', p. I-8.</ref> |
||
}} |
}} |
||
[[File:Dangerous bend symbol.png|thumb|left|Knuth's "Dangerous Bend" sign]] |
[[File:Dangerous bend symbol.png|thumb|left|Knuth's "Dangerous Bend" sign]] |
Revision as of 06:35, 4 September 2011
Certains passages sont destinés à prémunir le lecteur contre des erreurs graves, où il risquerait de tomber; ces passages sont signalés en marge par le signe ☡ («tournant dangereux»)
Some passages are designed to guard the reader against serious errors, where he risks falling; these passages are signposted in the margin by the sign ☡ ("dangerous bend")
— Nicholas Bourbaki's description of the symbol in several textbooks[1]
The dangerous bend symbol ☡ (unicode number x02621) was created by the Nicolas Bourbaki group of mathematicians and appears in the margins of mathematics books written by the group. It resembles a road sign that indicates a "dangerous bend" in the road ahead, and is used to mark passages tricky on a first reading or with an especially difficult argument.[2]
Others have used variations of the symbol in their textbooks, and computer scientist Donald Knuth used a more realistic road-sign depiction in his Metafont and TeX systems.[3]
Typography
In the LaTeX typesetting system (version 3), the dangerous bend symbol can be written as:[4]
\begin{danger} ... \end{danger} \begin{ddanger} ... \end{ddanger}.
References
- ^ See, for example, Théorie des ensembles, p. I-8.
- ^ Steven G. Krantz (2011), The Proof Is in the Pudding: The Changing Nature of Mathematical Proof, Springer, ISBN 0387489088, p. 92.
- ^ Donald Ervin Knuth (1984), The TeXbook, Addison-Wesley, ISBN 0201134489.
- ^ Frank Mittelbach, Michel Goossens, Johannes Braams, David Carlisle, Chris Rowley, Christine Detig, and Joachim Schrod (2004), The LaTeX Companion, Chapter 3: Basic Formatting Tools, Addison-Wesley.